As disclosed in Patent Literature 1, an exemplary vehicle body frame structure of a straddle-type vehicle includes a rear frame on which a seat is placed. The rear frame includes, at a front end portion thereof, a plurality of connected portions connected to a main frame. These connected portions are caused to overlap with the main frame from the side, and fastener members such as bolts are inserted in a vehicle width direction into a plurality of overlap portions of the rear frame and the main frame. In this way, the rear frame is connected to the main frame.